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Thursday, May 29, 2008 - 2:30 PM
588
Climate change effects on small upper courses of streams: An experimental approach
Piet F. M. Verdonschot and T.B.M. Dekkers. Centre for Ecosystem Studies, Alterra, Droevendaalsesteeg 3, P.O box 47, 6700 AA, Wageningen, Netherlands
Over the next century the air temperature in North-West Europe will rise with 4-6oC. In lowland streams going from source to about 1 km downstream a large gradual change in temperature of about four degrees occurs. An experiment was set up to test the effects of climate induced temperature rise on the in-stream organisms. 4x4 artificial streams were used, with one control (10oC) and three temperature treatments (13.8oC, 17oC and 21oC) to simulate current and future maximum temperatures in summer. Three trichopterans and the macrophyte Berula erecta with accompanying diatom community were collected from the stream ‘Springendalse beek’ and placed in the artificial streams. For the first 4 weeks the artificial streams were kept at 10oC to settle. After these four weeks width of Trichoptera head capsules was measured, diatoms were sampled and plant growth was measured. Next the temperature regimes were installed. Sampling was repeated four and eight weeks later. Plant length increased with increasing temperature, but biomass was highest at 17oC. Differences in growth of trichopterans were found between treatments, and also biotic interaction between two species changed at the highest temperature probably due to predation. An increase in air temperature can have large effects on biomass production and biotic interactions in small lowland streams.
Web Page: climate, temperature, stream